Sleep apnea involves a brief cessation of breathing during sleep. There exist two types of sleep apnea: central sleep apnea (“CSA”), which is associated with the failure of the body to automatically initiate and control a respiratory cycle at the proper time; and obstructive sleep apnea (“OSA”), which is associated with a blockage of the airway.
The most common type of sleep apnea is central sleep apnea. Central sleep apnea typically causes cessation of substantially all respiratory effort during sleep. This condition may be developed after a heart attack, and is usually a contributing factor to heart failure and other cardiopulmonary disorders.
The other type of sleep apnea is obstructive sleep apnea. Obstructive sleep apnea is generally characterized by repetitive pauses in breathing during sleep due to upper airway obstruction or collapse and is commonly found in overweight people who snore or have oversized necks. When awake, muscle tone keeps the throat open. When asleep, the airway of the neck narrows and closes. The person struggles to breathe against the collapsed throat as if choking. As the patient wakes up, the muscles of the throat open the airway. Many patients with congestive heart failure (“CHF”) suffer from obstructive sleep apnea.
Heart condition is typically worsened by excessive stress during apnea. Thus, the detection of sleep apnea is important.
Sleep apnea, once diagnosed in a patient, may be treated through several methods, including continuous positive airway pressure (“CPAP”), and electrical stimulation of the heart, diaphragm, or upper airway muscles.
Presently, sleep apnea detection is accomplished by several methods, including the detection of respiration, such as by monitoring the transthoracic impedance and other techniques.